Ever since the advent of transporting cargo, maintaining the integrity of the transported goods has been an issue. Damaged product at arrival is often rejected, adding additional costs to the supplier. Thus, bracing cargo prior to shipment, in any form; has given rise to the generic term “dunnage”.
Most dunnage is disposable, and is often made from wood or wood by-products, which tend to emit dust or chaffing material, making it unsuitable for some cargo applications. The waste nature of these products also adds additional cost to the receiving warehouse or plant facility.
Those products which are binned or boxed, often suffer damage when shipped via rail car. Damage occurs during the “hump” process when rail cars are switched and connected to another car resultant in a controlled bump. Freight within the car moves back and forth thus creating damaged contents. When the freight bins or boxes are of a substantial weight, attendant “G” forces tend to severally damage the containers. In order to reduce the damage the shipper will insert dunnage (packing material) between the bins or boxes to reduce any void, thereby restraining the bin or boxes within the shipping container or freight car. Inflatable dunnage is often chosen to fill these voids and the inflatable dunnage may be Kraft bags (basically a paper bag lined with poly) which are not reusable as the bag is generally slit open to remove the dunnage. Alternatively, dunnage bags may be made from toughened vinyl, which may be inflated and deflated like a balloon, thereby creating a reusable bag.
The rubber industry packages raw rubber in containers that are smaller on the bottom and larger on the top (trapezoidal in shape). Thus, upon delivery to the user (tire manufacturer) the bins are unloaded with a special set of forks (on a fork-lift) which are capable of readily turning the bin upside down, thereby easily dumping the raw rubber into a receiving point in the manufacturing process. The “hump” forces experienced by the railcar tend to damage these bins and the raw rubber will not fall out of the bins. This means that the raw rubber must manually be removed using expensive labor. Similar, problems will occur when shipping liquids (i.e., the bin can be damaged and then the contents will leak).
Shippers of raw rubber have used inflatable dunnage bags, unfortunately, these bags are not ideal. The Kraft bags tend to rip and any protection afforded the bins simply disappears. On the other hand the use of the stronger reusable vinyl dunnage bags does not help. The inflatable bag will change its internal pressure with any change in ambient temperature. For example, if the temperature drops in the shipping container, the bag essentially deflates. If the temperature rises, then the pressure builds dramatically in the bag making the bag become hard. It should be noted that the same temperature effect is experienced by Kraft bags. In both cases any protection afforded by the bags simply disappears.
Thus a strong, resilient, non-chaffing, re-useable material which serves to protect product during shipment and which is not affected by temperature changes is needed by the shipping industry.